Q: worklight protecting mobile application using predefined security 'mobilesecuritytest' I am building a custom authenticator and login module, and i have went through the tutorials and information.
I am able to achieve the security using security test defined on adapter but i want to leverage on the worklight predefined security test 'mobilesecuritytest' with my customized realm which is as advised on the documentation.
I couldn't find much information on the usage except only configuration via the application-descriptor.xml.

A: You can find detailed information about security tests in the following blog post: Understanding predefined Worklight authentication realms and security tests. 
There is no much else to it. You define the structure of the security tes in authenticationConfig.xml and apply it on the environment in application-descriptor.xml.
Take note of figure #3, showing an example of the pre-defined mobileSecurityTest used with a custom authentication realm.

Quote:

As you can see, the structure of the security tests has remained
  unchanged, however it is no longer using the default
  wl_anonymousUserRealm to identify users but a MyUserAuthRealm created
  by developer.

